Both are very nice. Actually I am thinking of using a cluster (like 1 above) with split servers (like in 2) in openvz containers.

However, though the tutorial 1 by Till categorically states that it deals with "fail over, load balancing and high availability", but is it only me that I see no such things except syncing with unison /var/mail and /var/www?

However, though the tutorial 1 by Till categorically states that it deals with "fail over, load balancing and high availability", but is it only me that I see no such things except syncing with unison /var/mail and /var/www?

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Seems as if you did not read the full guide yet othwise you might have noticed that it contains also a synchronisation of the clinet databases trough mysql and it instructs you to install ispconfg as well in mirroe mode which does the configuration sync between the systems.

The complete setup required for this kind of failover is described in guide 1). All configuration mirroring etc. is done by ispconfig, all you have to do in case of a afilure is to switch the IP address like described by ovh or put a loadbalancer in front.

I have two physical servers at two different locations setup using this guide.

Could you please explain how to switch the IP?
Also, how put a loadbalancer in front, is there a guide to follow to set this up?

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This is totally dependend on where you have your servers. As an example if you are with ovh you have to either rend a cisco hardware load-balancer or switch your fail-over-IP via the API if one servers fails. You could also use a vRack for this.

With some providers (mostly when they provide a private network for your servers only) it's also possible to simply use a gratuitous arp to take over the IP address (and the traffic) from another machine.

With the most providers I know, it's only possible to use fail-over-IPs between machines in the same datecenter due to routing limitations.

Either way, you got to see what options are offered by your provider for this case.

hmmm ... that's not so easy in this case. If you don't have your own RIPE block which you can route yourself, your IPs are actually belonging to your provider and you are only renting them. It's very unlikely that your provider will allow you to route his IPs to a another provider.

I guess your only chance to switch your services from one server to another with this setup is to change your DNS to route to the other IP in case of failure. That's not really a great solution, because this means your services will be down until the dns propagation time is over, but the only solution I see in the moment.